Psychological determinants and predictors of outcomes in spinal cord stimulation: a systematic review

Abstract Spinal cord stimulation (SCS) has been proven to be an effective therapy for chronic persistent pain conditions. In addition to somatic and technical variables, the effectiveness of this therapy is also influenced by psychological factors. Despite the growing number of studies, there is currently no consensus on which factors predict outcomes of SCS treatment. The existence of this knowledge gap underscores the need for a systematic review to consolidate the current knowledge about the role of psychological factors in the efficacy of SCS. A comprehensive literature search was conducted for this systematic review. The protocol for this review was registered at the International Database of Systematic Reviews (PROSPERO, CRD42024572349). The data from the included studies were synthesized using an Excel overview. The Newcastle–Ottawa Scale was used to evaluate the quality of the included studies. After duplicate removal, 1733 studies were identified; 29 studies met the inclusion criteria. The multiple questionnaires used in the included articles to measure psychological factors were divided into 7 domains: fear/anxiety, depressive feelings, catastrophizing, sleep, social functioning, pain, and psychiatric problems. The results were subjected to analysis on a per-domain basis. The domains of fear/anxiety, catastrophizing, and depressive feelings were classified as partially predictive, meaning that the reviewed articles provided mixed evidence regarding their predictive value for SCS outcome. The remaining 4 domains were either inconclusive or nonpredictive of SCS outcome. These psychological factors should not be used in isolation for selection, but they can contribute to a comprehensive assessment before SCS. Significance Statement: In current practice, the predictive value of psychological factors within the scope of outcome in Spinal Cord Stimulation therapy is not always clear. This systematic review aimed to synthesize existing evidence to determine the extent to which psychological factors influence both short- and long-term SCS outcomes, thereby informing clinical decision-making and future research.